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ARS Home » Plains Area » El Reno, Oklahoma » Oklahoma and Central Plains Agricultural Research Center » Livestock, Forage and Pasture Management Research Unit » Research » Publications at this Location » Publication #419155
Research Project: Integrated Research to Enhance Forage and Food Production from Southern Great Plains Agroecosystems

Location: Livestock, Forage and Pasture Management Research Unit

Title: Measuring genetic diversity of Texas bluegrass and allele sharing with Kentucky bluegrass interspecific hybrids using genome-wide markers

Author
item Boerman, Nicholas
item Robbins, Matthew
item CHANDRA, AMBIKA - Texas A&M University
item BRENTANO, SAMANTHA - Novel Ag, Inc
item BRENTANO, TOM - Novel Ag, Inc
item Bushman, Bradley

Submitted to: G3: Genes, Genomes, Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2025
Publication Date: 6/20/2025
Citation: Boerman, N.A., Robbins, M.D., Chandra, A., Brentano, S., Brentano, T., Bushman, B.S. 2025. Measuring genetic diversity of Texas bluegrass and allele sharing with Kentucky bluegrass interspecific hybrids using genome-wide markers. G3: Genes, genomics, genetics. Article jkaf133. https://doi.org/10.1093/g3journal/jkaf133.
DOI: https://doi.org/10.1093/g3journal/jkaf133

Interpretive Summary: Texas bluegrass is a perennial cool season grass native to Oklahoma and Texas that is tolerant of the heat and droughts of the Southern Plains. Whereas, the important cool season turfgrass, Kentucky bluegrass, lacks the same stress tolerance. Interspecific crosses between the two species have been made in attempts to increase the heat and drought tolerance of Kentucky bluegrass. We developed and have made publicly available a contig-level reference assembly of the Texas bluegrass genome. Genotypes were called and the genetic diversity among Texas bluegrass populations and the proportion of Texas bluegrass genome recovered in interspecific lines were evaluated. Little divergence was observed among Texas bluegrasses, but advanced generation interspecific lines diverged from Texas bluegrass while sharing 62-74% of their genome with Texas bluegrass. The large proportion of Texas bluegrass genome recovered in interspecific lines increases the likelihood that heat and drought tolerance in bluegrass can be improved via interspecific hybridization.

Technical Abstract: Kentucky bluegrass is an important cool season turfgrass species. However, heat and drought tolerance is an issue. Interspecific hybridization with a related species, Texas bluegrass is an approach used to improve heat and drought tolerance. We report herein a contig assembly of Texas bluegrass that was completed and used to measure the population structure of Texas bluegrass, interspecific lines between Texas and Kentucky bluegrass, and the percent allele sharing between advanced interspecific lines and cultivars to Texas bluegrass. The contig assembly was comprised of 367 contigs and spanned 6.6 Gb, with a completeness of 98.6% as indicated by BUSCO orthologous gene alignment. It was used to call 14,504 high quality SNPs. A principal component analysis showed separation of populations across the first two PCs, but they only explained 21.5 and 11.1 percent of the variation across the Texas bluegrass populations. Advanced interspecific lines and cultivars diverged from Texas bluegrass while sharing 62-74% of their alleles with Texas bluegrass. Interspecific Texas x Kentucky bluegrasses could be important for improving heat and drought tolerance among bluegrasses.